Tag: electricity

Quizzes (16) Questions (87)

Questions Related to electricity

Multiple choice types of cells electricity physics

A cell constructed by coupling a standard copper electrode and a standard magnesium electrode has emf of $2.7$ volts. If the standard reduction potential of copper electrode of $+0.34\ V$, that of magnesium electrode is

  1. $+3.04\ V$
  2. $-3.04\ V$
  3. $+2.36\ V$
  4. $-2.36\ V$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cell EMF is E_cell = E_cathode - E_anode. Given E_cell = 2.7 V and E_copper = +0.34 V (cathode), then 2.7 = 0.34 - E_magnesium. Solving for E_magnesium gives 0.34 - 2.7 = -2.36 V.

Multiple choice physics electric charges and fields conductors and insulators introduction to electrostatics electricity

State whether true or false.
Metals as compared to non-metals are generally bad conductors of electricity.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Metals are good conductors of electricity while non metals are bad conductivity as metal has lot of free electrons and therefore conducts while non metal  does not have any free electron and does not conduct electricity.So the answer is false.

Multiple choice physics electric charges and fields conductors and insulators introduction to electrostatics electricity

State whether true or false.
A jute string can be used to make a circuit instead of metal wires,

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A jute string cannot be used to make a circuit as jute is an insulator and does not conduct electricity while metal is a conductor of electricity, hence, metal wires can be used to make a circuit.

Hence, given statement is false.

Multiple choice physics electric charges and fields conductors and insulators introduction to electrostatics electricity

Glass wool is a . . . . conductor of electricity.

  1. good

  2. bad

  3. very good

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Glass wool is an insulating material made from fibres of glass arranged using a binder into a texture similar to wool. The process traps many small pockets of air between the glass, and these small air pockets result in the thermal insulation properties.
Glass wool is produced in rolls or in slabs, with different thermal and mechanical properties. It may also be produced as a material that can be sprayed or applied in place, on the surface to be insulated.
They possess very low expansion property, remarkable thermal shock resistance, low thermal conductivity, excellent electrical insulation up to 1000 C, and excellent resistance to corrosion from molten metal. 
Hence, Glass wool is a poor conductor of electricity.

Multiple choice physics electric charges and fields conductors and insulators introduction to electrostatics electricity

Aluminium metal is :

  1. magnetic substance

  2. bad conductor of heat

  3. good conductor of electricity

  4. bad conductor of electricity
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The electrical conductivity of matter is dependent upon the atomic structure of the material from which the conductor is made. In any solid material, such as copper, the atoms which make up the molecular structure are bound firmly together. At room temperature, copper will contain a considerable amount of heat energy. Since heat energy is one method of removing electrons from their orbits, copper will contain many free electrons that can move from atom to atom. When not under the influence of an external force, these electrons move in a zigzag manner within the conductor. This movement is equal in all directions so that electrons are not lost or gained by any part of the conductor. When controlled by an external force, the electrons move generally in the same direction. The effect of this movement is felt almost instantly from one end of the conductor to the other. This electron movement is called an ELECTRIC CURRENT.
Some metals are better conductors of electricity than others. Silver, copper, gold, and aluminum are materials with many free electrons and make good conductors. Silver is the best conductor, followed by copper, gold, and aluminum. Copper is used more often than silver because of cost. Aluminum is used where weight is a major consideration, such as in high-tension power lines, with long spans between supports. Gold is used where oxidation or corrosion is a consideration and a good conductivity is required.
Hence, Aluminium is a good conductor of electricity.

Multiple choice physics electric charges and fields conductors and insulators introduction to electrostatics electricity

Mica is a ____ conductor of electricity.

  1. good

  2. bad

  3. positive

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The electrical and thermal conduction properties of a material can be similar or very different, in metals the electrical and thermal conductivity is due to free electrons, in non-metals thermal conductivity has nothing to do with free electrons, but more to do with lattice vibrations (that is, phonons). 
So mica has good thermal conductivity due to phonons, but doesn't have sufficient free electrons and a very high resistance to be a good conductor of electricity.
Hence, Mica is a poor or bad conductor of electricity.

Multiple choice physics electric charges and fields conductors and insulators introduction to electrostatics electricity

Which of the following is an electrical insulator :

  1. Aluminium

  2. Gold

  3. Rubber

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Metals are generally good conductors of electricity. So, Gold and Aluminium are good conductors of electricity. 
Non-metals are poor conductors of electricity.
So rubber, being a non-metal, is an electrical insulator and hence a poor conductor of electricity.